Centrifugal machine



Patented., ug. 16, 1938 NITED STATES PATENT OFFICE CENTRIFUGAL MACHINE Application February 27, 1935, Serial No. 8,458

4 Claims. (Cl. 233-20) The present invention relates to centrifugal separators designed to separate sludge from liquids, the term sludge as used herein being considered as designating not only impurities, but

5 any materials including a large proportion of solids of higher specific gravity than the liquids in which they are suspended.

The invention relates more particularly to that type of centrifugal separators in which the solids are discharged through peripheral ports in the bowl structure and still more particularly to an improved means for closing such discharge ports.

In Nyrop application, Serial No. 700,687, led December 2, 1933 and since eventuated into Patent No. 2,091,329, is shown a centrifugal separator of this type in which a circlunferential piston is provided for sealing the outlet ports, and which is' operated in accordance with the differential forces -exerted by the liquid Within the bowl and 0 a liquid introduced to 'actuate the piston in one direction. I have found that with this structure, there has sometimes been a failure in the piston to completely uncover the ports, and as a consequence adetrimental amount of wire-drawing and erosion at the sealing edge of the piston has occurred. Furthermore, under some conditions of operation, the piston has failed to open quickly enough to 'effect a complete opening of the ports before the effective pressure within the separating bowl has been spent.

It is an object of this invention to overcome the difculties and disadvantages above pointed out, and toward this end I have provided a hydraulically operated piston which is positively actuated in both directions of movement.

Another object of the invention; consists in providing adequate packing means between the bowl structure and the reciprocating sealing piston.

Further andimportant objects Will in part be evident as this description proceeds and will in part be more fully explained.

In this specification and in the annexed drawing, the invention is illustrated in what is now considered the preferred embodiment, but it is to be understood that the invention is not limited to the particular form shown, because it may be embodied in other forms and it is also to be understood that in and by the claims following the description, it is my desire to cover the invention in whatever form it may be embodied.

In the drawing, the single figure is a central axial sectional View illustrating one form the invention may take.

Referring to the drawing by reference'characters, the shaft II of the machine may be driven centrifugal bowl.

to an upper bowl member or cove` I5 in any desired manner, such as by screws, these portions being secured together in spaced relationship in order to afford provisionv for a discharge opening I6 between the'parts I2 and I5 of the bowl.

The interior of the bowl tapers from both ends toward the middle and has a maximum interior diameter at the z one of junction between a gasket 28 and a piston 21 in the neighborhood of the discharge opening I6. A central distributing feed tube I'I is secured to the bowl in such a position as to feed the material to be treated into the bottom portion of the bowl and a suitable disc inset I8 is also secured within the bowl, the disc inset and distributing tube being secured in'place by means of a nut I9 which is threaded on the upper outer circumference of the A distributing tube.

Accelerating wings 24 are provided and these wings can be fixed to rings 25 in order to facilltate their removal for cleaning. A skimming plate 20 directs the lighter efduent separated .from the liquid within the bowl to a discharge outlet 23 and a heavier eiuent through openings 22 under the control of an interchaangeable weir'2l. d

The bowl members I2 and I4 are circumferentially spaced in order to provide therebetween a groove in which a piston 26 may reciprocate. The piston 26 is provided with an upstanding body member 21 which is adapted to contact a sealing gasketl 28 in the upper bowl member I5. The

lower end of the piston 26 has an inwardly projecting boss 29 which is loosely engaged by a circumferential ring 30 which is adapted to move in a recess 3|. Piston 26 is provided with ports 32 spaced at intervals about its circumference and in communication with a circumferential groove 33 on the inner face of the piston 26. When the piston 26 abuts gasket 28 to close the circumferential discharge port I6, port 32 registers with an opening 34 in the lower bowl member I4. The ring 30 is positioned within the lower bowl member to provide a certain lamount of clearance 35 between the same and the bowl member l2 for a purpose which will hereinafter be described.

Part I4 of the lower bowl is provided with a neck 36 which has therein circumferential grooves 31 and 3B. Groove 31 communicates with a duct 39 which in turnA opens into the circumferential chamber 3I bneath the piston and member 30. Groove 36 communicates by means of a duct 40 withga second duct 4I communicating with the space 35 between the ring 30 and the inner bowl member I2. Jets 42 and 43 are provided to direct water or other liquid into the grooves 31 and 38 respectively for a purpose which will hereinafter be more fully described.

In order to lprovide a tight seal between the bowl member l2 and the piston 26, I have provided a packing member of peculiar construction located in a circumferential groove in the inner bowl member I2. In the packing member, 44 and 45 represent circumferential anged rings which are held in position and in spaced relation by a spacer ring 46, between a shoulder in the circumferential groove and a retaining ring I2' which is aillxed to the bowl member I2 in any suitable manner after the packing member has been placed in position. To the rear of the flanged ring 44, which is made of exible metal, is xed a lead weight 41 which performs the function of forcing the vertical portion of ring 44 into tight engagement with the piston 26 under the influence of centrifugal force. I have found that a metal to metal seal is not entirely satisfactory under all conditions of operation, and for this reason, I have modified the sealing effect of the ring 45 by attaching thereto a band of fabric material 48 which is held between the vertical portion of the anged ring 45 and a lead strap 49 which is suitably attached tg the ring 45. With this arrangement, I have been able to secure a very satisfactory seal under-widely varying conditions of operation. The extension 5D of the circumferential groove in member I2 may ordinarily be iilled with a plastic sealing material, such as, for instance, graphite.

In order to prevent liquid from .passing between they piston 26 and the bowl member I4, I

have provided a packing ring 5I which extends` into contact with the piston 26 and which'is held in place in a circumferential groove in the base of member I4 by means of a retaining ring 52.

In the normal operation of the machine, let'it be assumed that the piston 26 has been closed by means of liquid from jet 42 which by centrifugal force is led to the duct 39, into the chamber 3I and under the lower endof the piston 26 where a considerable hydraulic pressure is developed. An open outlet 53 limits the extent to which liquid is retained in the chamber 3| and-'this limit extends to the inner edge of the boss 2'3. Now, with the piston 26 in its upper position and in tight contact with the gasket 28, the material to be treated `may be fed into the distributing tube I1 and the separatormay be operated until a considerable portion of sludge has collected at the zone defined by' the outer-circumferential edges of the bowl member I2 and I5. Ify it now becomes desirable to open outlet port I6, the piston 26 may be quickly vand positively actuated by admitting liquid from the jet 43 to the groove 38 into the channel 40 and from there through the channel 4I to the clearance space 35. Centrifugal force causes a considerable hydraulic pressure to de- `velop above the member 30 and since thefarea against which this hydraulicpressure operates is 'greater than the area of the lower end of the piston 26, the pressure within the outer edge of chamber 3| is quickly overcome and the piston 26 is immediately lowered, liquid from the chamber 3| beingdischarged through the oulet 53. Inasmuch as the lower end of the piston 26 and the ring 30 are only in loose'engagement, liquid from the space 35 quickly iinds its'way over the ring'30, into the circumferentialgroove 33 in piston 26 fand through the discharge ports 32 and 34. Thus, the closure mechanism is quickly prepared for another cycle of operation, for when the liquid supply from the jet 43 is cut oi and liquid .from the jet 42 is supplied, pressure again quickly develops under the lower end of the piston 26 and carries the same upwardly into closed position and with it member 30.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A centrifugal separator adapted to be rotated to eiect the continuous discharge of a liquid eiiluent during the concentration of suspended solid material within the bowl, said separator including a cover and a base having a discharge passage therebetween, the base thereof comprising an annular outer casing member and an inner sludge supporting member spaced therefrom to form a narrow sealing piston chamber therebetween to receive such piston and support the same throughout substantially its .entire length, an enlarged chamber at'the bottom of the said sealing piston chamber, a piston mounted within the bowl for reciprocation within said chamber, aA sealing member within said bowl and beyond said chamber adapted to be abutted by one end of said piston in one position to prevent the undesired discharge of sludge through the discharge passage, a l"radial flange projectinginwardly from said piston and into said enlarged chamber, means for admitting liquid to a space above said' radial iiange for moving said piston into slude discharging position, and means for admitting liquid under said piston for moving said piston to sludge retaining position.

2. A centrifugal separator adapted to be rotated to effect the continuous discharge of a liquidefuent during the concentration of suspended solid material within the bowl, said separator including al cover and a base having a discharge passage therebetween, the base thereof compris-v ing an annular outer casing member and Ian inner sludge-supporting member spaced therefrom to form a narrow annular sealing piston chamber therebetween to receive such piston and support the same throughout substantially its entire length, an enlarged chamber at the -bottom of the said sealing pistonchamber, an annular piston mounted within the bowl for reciprocation within said chamber, a sealing member within said bowl and beyond -said chamber adapted to beabutted by one end-of said piston in one position to prevent the undesired discharge of sludge through the discharge passage, a radial flange projecting inwardly from said piston and into said enlarged chamber, means for admitting liquid to a space above said radial flange for moving said piston into sludge discharging position, and means for admitting liquid under said piston for moving said piston to sludge retaining position. Y

3. A centrifugal separator adapted to be rotated to effect the continuous discharge of a liquid eluent during the concentration of suspended solid material within the bowl, said separator including a. cover anda base having a discharge passage therebetween, the base thereof comprising an annular outer casing member and an inner form a narrow sealing piston chamber therebetween to receive such piston and support the same throughout substantially its entire length, an enlarged chamber at the bottom of the said sealing piston chamber, a piston mounted within the bowl for` reciprocation within said chamber, a,

sealing member within said bowl and beyond said chamber adapted to be abutted by one end Aoi said piston in one position -to prevent the undesired discharge of sludge through the discharge passage, a radial ilange projecting inwardly from said piston and Yinto said enlarged chamber and having operating contact with said piston for moving the same into sludge dischargingv position only, means for admitting liquid to a space above said radial ange for moving said piston into sludge discharging position, and means for admitting liquid under said piston for moving said piston to sludge retaining position:

a. A centrifugal separator adapted to be rotated to efl'ect the continuous discharge of a liq-4 uid eiiluent during the concentration o1' suspended solid material within the bowl, said separator ln- `cluding a cover and a base having a dischargev sludge supporting member spaced theretron to passage therebetween, the base thereof comprising an annular outer'casing member and an inf nersludge supporting member spaced therefrom to form a narrow annular sealing piston chamber therebetween to receive such piston and sup` d port the same throughout substantially its entire length, an enlarged chamber at the bottom of said sealing piston chamber, anannular piston mounted within the bowl for reciprocation within said chamber, a sealing member within l0 said bowl and beyond said chamber adapted tzr be abutted by one end of said piston in one position to prevent the undesired discharge oi i sludge through the dischargeV` passage, a radial ange projecting inwardly from said piston and 15.

into said enlarged chamber and having operative contact with said piston for moving the same into sludge discharging position only, a liquid head limiting port in said. bowl at the inner radius of said piston, means forladmitting liquid to a 20 space above said radial tlar'ige for moving said piston into sludge discharging position and means for admitting liquid under said piston :for moving said piston to sludge retaining position.

' WILMER H. BATH. 25 

